The Los Angeles Lakers' playoff outlook took a blow Tuesday when the NBA suspended forward Metta World Peace seven games without pay for the devastating elbow to the head of Oklahoma City Thunder guard James Harden in Sunday's game.

World Peace floored Harden with the elbow and was ejected on a flagrant foul-2 in the second quarter of the Lakers' 114-106 double-overtime victory. Harden, who did not return to play, complained of a headache but was cleared to return to Oklahoma City with the team late Sunday.

"The concussion suffered by James Harden demonstrates the danger posed by violent acts of this kind, particularly when they are directed at the head area," NBA Commissioner David Stern said in a statement. "We remain committed to taking necessary measures to protect the safety of NBA players, including the imposition of appropriate penalties for players with a history of on-court altercations."

Harden is an invaluable sixth man for the Thunder, averaging career highs of 16.8 points, 4.1 rebounds, 3.7 assists and 31.4 minutes. He was at shootaround Tuesday but did not play Tuesday night against the Sacramento Kings.

"I hope James Harden is ok," World Peace said in a statement. "I apologize to the Oklahoma City Thunder fans and the OKC organization. I look forward to getting back on the floor with my teammates and competing for the Lakers and the Lakers' fans."

The first game missed for World Peace, who canceled a scheduled Tuesday appearance on Conan O'Brien's TBS late show, will be the Lakers' regular-season finale at the Sacramento Kings on Thursday. World Peace is earning $6.79 million for this 66-game, lockout-shortened season.

World Peace, who changed his name from Ron Artest in September, had avoided major controversy on the court since he was suspended for 86 games in November 2004 for engaging in the brawl against the Detroit Pistons at the Palace of Auburn Hills while playing for the Indiana Pacers.

The seven-game suspension this time ties for his second longest, in July 2007, when he was with the Sacramento Kings, for pleading "nolo contendre" to infliction of injury on a spouse.

This is the 13th time World Peace has been suspended in his 13-year career but only the second time in his three seasons with the Lakers. That was for one game, last May in the playoffs against the Dallas Mavericks, for swinging his arm and striking the face of guard J.J. Barea.

Just last April, World Peace won the NBA's J. Walter Kennedy Citizenship Award, primarily for his work in mental health awareness.

"Metta has for the most part been a model citizen both on and off the court since joining the Lakers," Lakers general manager Mitch Kupchak said in a statement.

"Still, his most recent lapse in judgment is not to be condoned or accepted. His actions could have seriously injured another player, and his absence during this suspension will hurt our team, as well. While we accept the league's decision, we will be supportive of Metta and try to help him be more professional on the court."

If the Lakers win to maintain their No. 3 seed in the Western Conference, they also won't have World Peace for Games 1-6 of their first-round playoff series, if they should need that many, against the No. 6 Denver Nuggets or Dallas Mavericks. And the suspension could carry over into the next round if the Lakers win in fewer than seven games. The Lakers are 4-0 vs. the Mavericks and 3-1 vs. the Nuggets this season.

If the Lakers lose to the Kings and the Los Angeles Clippers win their last two games, the Lakers will drop to the No. 4 seed for a series against the No. 5 Memphis Grizzlies. The Lakers won that season series 2-1, but the Grizzlies didn't have All-Star power forward Zach Randolph for their two losses because of a knee injury. Not having World Peace would be especially costly against a physical, bruising team such as Memphis.

Sunday, the powerfully built 6-7, 260-pound World Peace had dunked over Kevin Durant and Serge Ibaka on a fast break and was headed back upcourt when he ran into Harden. While pounding his chest with his right arm, World Peace raised his left elbow over Harden's shoulder and cleanly hit Harden in the back of the skull. Harden fell to the court and stayed down for about a minute before heading to the locker room. He didn't return to the game but traveled back home with the Thunder.

Although Harden did not play Tuesday, in the morning he wrote on Twitter, "Im solid. Feeling good. Appreciate y'all for checking on me!!"

The Thunder are locked in as the No. 2 seed in the West, behind the San Antonio Spurs.

Any loss of time for Harden could be devastating for the Thunder, considered one of the top contenders for the NBA title. Harden is the team's third leading scorer, behind All-Stars Kevin Durant and Russell Westbrook.

"I think he deserved more ... maybe 10 games," TNT's Shaquille O'Neal said. "I don't like to talk about 'ifs' but if (James) Harden would've turned to the left a little bit, we could've had a Rudy Tomjanovich situation on our hands.

"Don't get me wrong, I'm a connoisseur of throwing elbows; I used to throw elbows all the time. But for him to say he didn't do that on purpose? There is an old saying that goes around the locker room, 'The tape doesn't lie.' I've seen every angle and it didn't look accidental to me."

According to league policy on flagrant fouls it considers the severity of the contact; whether or not a "legitimate basketball play" such as a shot block was being made; if the contact was reckless; if there is a wind-up and follow-through after making contact; if there was a resulting injury and the degree of severity of the injury; and whether or not the episode led to an altercation.

In February, Minnesota Timberwolves forward Kevin Love was hit with a two-game suspension after stepping on the face and body of a fallen Luis Scola of the Houston Rockets. It was Love's first suspension of his four-year career.

World Peace is averaging 7.7 eight points, his lowest career output, but had reached double figures in seven consecutive games, including 12 points in the first half against the Thunder. Before that offensive spurt, it had taken him until March 4 to total seven double-digit scoring games for the season.

Losing World Peace hurts the Lakers not only because of the timing but also because the versatile perimeter defender had been in a positive groove. This has been his best month, including a season-high 26 points in an April 11 win against the Spurs.

Sunday's flagrant was World Peace's first this season.

"I got real emotional and excited, and it was unfortunate that James had to get hit with the unintentional elbow," said World Peace after the game. "I apologize to the Thunder and James Harden. It was just unfortunate."

Hours later he tweeted: "I just watched the replay again..... Oooo.. My celebration of the dunk really was too much... Didn't even see James ..... Omg... Looks bad"

The suspension leaves the Lakers thin at forward. It could mean more playing time for forward Devin Ebanks, who began the season as the starting small forward in coach Mike Brown's motion offense. World Peace started his first two seasons in Los Angeles under then-coach Phil Jackson but moved to a sixth man role this year.

Tuesday, the Lakers' Twitter site said Ebanks apparently bruised the ring and middle fingers on this non-shooting left hand after dropping a dumbbell while lifting weights and was "probable" for Thursday's game against the Kings.

But forward Matt Barnes definitely won't play. He is rehabbing an ankle and won't travel with the team to Sacramento.

Reaction was swift around the league about the incident and suspension:

•Grizzlies guard Tony Allen on 730 AM Yahoo! Sports Radio Memphis - "That was some MMA stuff. If that was me, you might have to meet me after the game."

•Thunder center Kendrick Perkins, who initially said World Peace didn't mean to hurt Harden, but changed his mind after seeing the replays - "It was just uncalled for. I really don't have any sympathy for a guy that does something like that. He could have really hurt James."

•TNT's Charles Barkley - "I knew (the suspension) was going to be the first round of the playoffs. I don't think that's a fair or unfair suspension. If it was 10 games, that would've been fair. I knew it was going to be between five and 10 but I'm surprised they didn't make it just the first round of the playoffs because he could come back for a Game 7. But he can't do that, when you start hitting people in the head ... That's dangerous."

•TNT's Kenny Smith: "I think the suspension was warranted. There is a difference with NBA players, they get paid over 82 games. ... They don't get paid for the playoff games. So I don't know if it's going to affect him financially as if it would've been seven regular-season games. Overall, he shouldn't be on the court for seven games."

From RT @theScoreTicker on Twitter: "#Lakers Metta World Peace has been suspended in more NBA games (116) than Greg Oden has played in his career (82)."

Thunder coach Scott Brooks did not want to engage in speculation as to any suspension for World Peace.

"That's not something I focus on," he said. "I focus on James and our team. The league, they do a great job taking care of what needs to be taken care of."

Here is the list of World Peace's previous regular-season suspensions, from the NBA, on the dates the league issued them:

Feb. 21, 2001: As a Chicago Bull, one game for his role in an in-game altercation with the Milwaukee Bucks' Glenn Robinson

Jan. 4, 2003: As an Indiana Pacer, three games for throwing a television monitor and a cameraman's camera onto the floor following the conclusion of a game vs. the New York Knicks.

Jan. 29, 2003: With the Pacers, four games for confronting and making physical contact with Miami Heat coach Pat Riley, for taunting the Miami bench, for committing a flagrant foul-2 on Caron Butler (pushing him into the stands) and making an obscene gesture toward fans.

March 9, 2003: With the Pacers, one game for exceeding the maximum allowable flagrant foul points in a season.

March 13, 2003: With the Pacers, one game for again exceeding the maximum allowable flagrant foul points in a season.

March 20, 2003: With the Pacers, two games for again exceeding the maximum allowable flagrant foul points in a season.

March 19, 2004: With the Pacers, one game for hitting the Portland Trail Blazers' Derek Anderson in the head with a forearm.

April 19, 2004: With the Pacers, one game for leaving the immediate vicinity of his team's bench during an altercation.

Nov. 21, 2004: With the Pacers, 73 games (and 13 games during the team's playoff run) for his role in an in-game incident between Indiana and the Detroit Pistons.

April 24, 2006: With the Kings, one game for making contact with the head of San Antonio Spur Manu Ginobili with his forearm.

July 14, 2007: With the Kings, seven games for pleading "nolo contendre" to infliction of injury on a spouse.

May 5, 2011: With the Lakers, one game for swinging his arm and striking the face of the Dallas Mavericks' J.J. Barea.

Here are the NBA's five stiffest non-drug-related suspensions:

73 games, Nov. 21, 2004: Artest for his role in the brawl at the Palace of Auburn Hills - For his role in an in-game incident between Indiana and Detroit